Installation for the expansion of a liquefied gas



Sept. 11, 1962 s. 1.. E. VIGNIER 3,053,054

INSTALLATION FOR THE EXPANSION OF A LIQUEFIED GAS Filed Jan. 23, 1961 2 Sheets-Sheet 1 Inven'i'o serg Lou s Eujene V/ nl er m hm? 71 0 W p 1962 s. L. E. VIGNIER INSTALLATION FOR THE EXPANSION OF A LIQUEFIED GAS Filed Jan. 23, l 36l 2 Sheets-Sheet 2 IrvrchTo erg Lowsgu ene Vzjmer ,6 Aug fiwuvhflafu Patented Sept. 11, 1962 3,053,054 INSTALLATIDN FOR THE EXPANSION OF A LIQUEFIED GAS Serge Louis Eugene Vignier, Paris, France, assignor to Boudet et Cie, Saint-Ouen, France, and Compagnie Centrale de Mines et Mctallurgie Sicli, Paris, France, both French companies Filed Jan. 23, 1961, Ser. No. 84,284 Claims priority, application France Jan. 25, 1960 3 Claims. (CI. 62-52) The invention concerns an installation for the expansion of a liquefied gas, more especially carbon dioxide gas, contained in a chamber under pressure. 7

Utilization of liquid carbon dioxide has advantages, especially that a stock thereof can be held which is not bulky with the large volume of usable gas; the pressure is constant; it presents however a great disadvantage of frosting when this gas is required to be used under medium or loW pressures.

Known installations for expansion of liquid carbon dioxide gas comprise a classical expander preceded by a reheater or a dryer, sometimes both together, in case of need with the adjunction of a capacity plug.

An object of the present invention is to provide an installation for expansion of gas under pressure, more especially carbon dioxide, which obviates frosting inherent in known installations.

According to the present invention an installation for the expansion of a liquefied gas, more especially carbon dioxide, contained in a container under pressure (high pressure) is characterised in that it comprises a vaporization chamber provided with means for heating and adapted to be fed by liquefied gas from a container under pressure by the intermediary of a pressure sensitive regulator (medium pressure) for the gas in the vaporization chamber, the outlet from the vaporization chamber being provided with an expander adapted to reduce the pressure of the gas from a medium pressure value to a low pressure value for utilization.

In this installation the gas is no longer admitted into the expander in the liquid state but in the gaseous state which eliminates practically all the frosting in the expander. The admission of gas into the vaporization chamber may be effected in the form of a liquid jet over the whole of its surface, the regulator interposed on this jet not being submitted to the effects of frosting because the gas is in a liquid state when it enters and when it is discharged.

Preferably the vaporization chamber is connected to the low pressure expander by the intermediary of an overheating receptacle at a suitable temperature.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a diagrammatic view of an embodiment of an installation for the expansion of liquid carbon dioxide constructed in accordance with the invention; and

FIG. 2 is a diagrammatic view of an alternative embodiment.

The installation shown in FIG. 1 comprises a source of liquid carbon dioxide constituted by a flask 1 vaporization chamber 2 fed with liquid gas, from the flask 1, by conduit 3 on which there is interposed a supply regulator 4, an expander 5 being connected to an outlet from the vaporization chamber 2 by a conduit 6, an outlet of the expander 5 being provided with a conduit 7 adapted to be connected to any apparatus using gaseous carbon dioxide at low pressure.

The conduit 3 for the admission of liquefied gas discharges into the vaporization chamber 2 by means of a calibrated nozzle or jet 11 which limits the supply of liquid gas in such a way that this cannot pass to the gaseous state in the conduit 3 and is always admitted in a liquid form into the vaporization chamber 2.

The opening and the closing of the supply regulator is controlled by the pressure which exists in the vaporization chamber 2. This regulator is of an appropriate type and there has been indicated schematically, by a conduit 12, the connection between the vaporization chamber 2 and the regulator for the control of this latter.

The vaporization chamber 2 is provided with means for heating, constituted by a heating rod 14 fed from a main supply 15. The expander 5 is arranged in a chamber 16, also provided with heating means, represented likewise in this example by a heating rod 17 fed from the main supply 15.

There has also been indicated a high pressure gauge 21 mounted on the outlet conduit from the flask 1, a medium pressure safety valve 22 connected to the vaporization chamber 2, a medium pressure gauge "18 and a thermometer 19 mounted on the chamber 2, a medium pressure gauge 20 and a low pressure gauge 24 mounted respectively on the entry and exit sockets of the expander 5 and finally a low pressure safety valve 23 connected to the utilization conduit 7.

There are disposed filters 25, 26 respectively on the conduit 3 for admission of liquid gas and on the conduit 6 for admission of vaporized gas.

The constancy of the temperature inside the vaporization chamber 2 is assured by any known means suitable for regulating the feed of the heating rod '14, for example by means of a thermostat 27.

Means for injecting nitrogen into vaporization chamber 2, comprise a source 35 of nitrogen under pressure, for example a flask, connected to a nozzle 36 mounted on the vaporization chamber 2 by the intermediary of a regulator 37 controlled, as indicated by the conduit 38, by the supply of gas in the utilization conduit 7.

The installation functions as follows:

Liquid gas under high pressure contained in the flask 1 is admitted by the regulator 4 and the filter 25 into the jet 1]. from whence it escapes in becoming vaporized into the reheating chamber 2. From there it crosses the filter 26 and the expander 5 from where it emerges at low utilization pressure to the conduit 7.

The regulator 4 assures a suitable supply of liquid gas as a function of the pressure of gas which exists in the vaporization chamber 2 (medium pressure) and the expander 5 lowers the pressure of gas from medium pressure to low pressure.

Frosting in the regulator 4 cannot occur as the gas is always in the liquid state at the entry to the regulator and at the outlet therefrom. The vaporization in the chamber 2 does not give rise to frosting even though this chamber is reheated.

It can be seen that this installation is of particularly small size, that it permits a regulatable expansion of the gaseous phase of carbon dioxide and that the reheating of the expander, especially for large supplies, permits the augmentation of the calorific yield of the installation by compensating the heat absorbed during expansion of the gas.

In the variant illustrated in FIG. 2 there is likewise shown the flask 1 for liquefied gas connected to the vaporization chamber 2 by the conduit 3 including the supply regulator 4, the expander 5 connected by the conduit 6 to the chamber 2 and by the conduit 7 to the apparatus utilizing the gas, the nozzle or calibrated jet 11 limiting the supply of liquid gas in the chamber 2, the conduit 12 transmitting to the regulator 4 the pressure of the chamber 2, an electric resistance 14, fed by the mains supply 15 and heating the chamber 2, controlled by the thermostat 27, the medium pressure gauge 18 measuring the pressure in the chamber 2, the high pressure gauge 21 at the outlet from the flask 1, the safety valve 22 of the chamber 2 and the low pressure gauge 24 at the outlet of the expander 5.

However on the conduit 6 connecting the vaporization chamber 2 with the expander there is interposed an overheating receptacle consitituted, in this example, by a coil 41.

This overheating coil 41 is disposed in a bottomless cylindrical vat 4-2 which is itself disposed in a heated receptacle 43 filled with a fluid such as oil, glycol, glycerined water, gas, vapour, etc. the coil 41 is immersed in this fluid. The outer surface of the vaporization cham ber 2 which is water-tight is likewise immersed in the fluid contained in the chamber 43.

The chamber 43 is provided, in its upper part, with an orifice 45 for discharge to atmosphere and, in its lower part, it is provided with an emptying tap 46.

The overheating coil 41 is heated by an electric resistance 47 disposed in the bottomless vat 42 and likewise fed from the electric mains 15.

The thermostat 27, which regulates the temperature inside the vaporization chamber 2, controls a relay 48 for the feeding of the heating resistance 14 and in a similar fashion the temperature of the overheating receptacle 41 is regulated by the feed of an electric resistance 47 through the control of a thermostat 49 disposed in the chamber 43 and from a thermostatic relay 51 interposed in the feed circuit of the resistance 47.

The outlet from the flask 1 is provided with a filter 52 and if necessary a dryer could also be provided.

The functioning of the variant is similar to the one of the embodiment illustrated in FIG. 1. The only difference is that the overheating receptacle 41 augments the heat exchange surface and regulates the pilot pressure to which the regulating device 4 is submitted.

While a particular embodiment of this invention has been illustrated and described herein, it is intended that this invention be not limited to such disclosure, and changes and modifications can be made and incorporated within the scope of the claims.

I claim:

1. A liquefied gas vaporizing apparatus including a heat insulated enclosure filled with a fluid medium, first heating means for heating said fluid medium, a vaporizing chamber arranged in said enclosure and provided with a liquefied gas inlet and an outlet for the gas to be delivered, a liquefied gas flow restricting nozzle at said inlet, a supply duct connected to said nozzle and adapted to be connected to a source of liquefied gas, a control valve inserted in said supply duct and adapted to provide either for full flow of liquefied gas from said source to said nozzle or for complete interruption of said flow, in response to modification in the gas pressure prevailing in said vaporizing chamber between two predetermined lower and upper limit pressures respectively, second heating means independent from said first heating means and arranged within said vaporizing chamber, and means for controlling said second heating means in response to the temperature prevailing in said vaporizing chamber.

2. A liquefied gas vaporizing apparatus according to claim 1, further comprising a superheating receptacle also arranged in said enclosure and having an inlet connected to the outlet of said vaporizing chamber and an outlet for delivering the gas, the heating means for said superheating receptacle being constituted by said first heating means. i

3. A liquefied gas vaporizing apparatus as defined in claim 1, further comprising means for injecting nitrogen under pressure into said vaporizing chamber.

References Cited in the file of this patent UNITED STATES PATENTS 

